1. Field of the Invention
The invention relates to an inhalator for dispensing an aerosol comprising a dosage counting device, a housing part, and an aerosol dispensing container displaceably arranged relative to the housing part along its longitudinal axis.
2. Discussion of the Relevant Art
Such an inhalator is known from EP-A1-0 254 391. In these conventional inhalators, an aerosol dispensing container is displaceably inserted into a tubular portion of a housing part. The dispensing container comprises a spraying tube which is guided out of a head area of the dispensing container, which spraying tube is inserted in a sealed manner into a spraying socket portion which is formed as a monolithic part of the housing. For dispensing a predetermined dosage of the medium stored in the dispensing container, a pressure force is applied to a bottom portion of the dispensing container and the container is briefly forced into the housing. Via the spraying tube inserted into the spraying socket a valve mechanism is opened for a moment and a predetermined amount of the medium contained in the storage container is sprayed via the spraying head. In a lateral area of the housing an indicator wheel is provided which is rotatably supported and which is rotated farther for each dispensing stroke of the inhalator by means of a step-down gear system by a minimal rotational distance. The indicator wheel is provided with several filling level indicating marks which can be read by means of a window portion for a successive rotation of the indicator wheel. When the dispensing container is almost completely emptied, a corresponding symbol is visible in the window, and this signalizes to the user that the dispensing container is substantially completely empty. By means of overfilling of the dispensing container at the manufacturing site by approximately 10 to 15%, it is ensured that upon reaching this end mark a sufficient amount of active substance is still stored in the dispensing container.
The overfilling of the dispensing container carried out at the manufacturing site, in particular, when filling with comparatively expensive active substances, results in an increase in cost of the inhalator. Also, with regard to environmental protection considerations an overfilling of the dispensing container to the degree that has been conventional up to now appears to be problematic.
The invention has therefore the object to provide an inhalator for dispensing aerosols which is characterized by a high functional reliability and a dosage counting device improved with respect to readability and indication precision.
This object is solved according to the invention by an inhalator having a first counting ring which is arranged coaxially to the longitudinal axis of the aerosol dispensing container and is rotatable about this longitudinal axis; a second counting ring which is arranged coaxially to the first counting ring and can be directly coupled therewith and is rotatable relative thereto; counting ring switching device for rotation of the first counting ring upon actuation of the inhalator; and a coupling device for coupling the second counting ring with the first counting ring for a stepwise rotation of the second counting ring together with the first counting ring; wherein the counting ring switching device has an actuation portion and a switching finger coupled therewith, which for rotation of the corresponding counting ring can be brought into engagement with control elements thereof.
In this way, it is possible in an advantageous manner to provide an inhalator which can be produced with respect to manufacturing technological aspects in a beneficial way and with which, as needed, each individual dosage stroke is counted and indicated. In addition to the thus obtained reliable monitoring of residual filling amounts of the active substance medium stored in the inhalator, it is moreover possible to monitor the administration of the dosage aerosols in correspondence with the prescription in an improved way. The inventively embodied dosage counting device makes possible, for example, counting from 0 to approximately 200 of the individual dosage amounts. As an alternative to this, it is also possible to provide the number arrangement on the two counting rings such that dosage counting is possible in a descending order starting at the maximum stroke number. Counting can be performed successively in the descending order, for example, starting with the number 200, wherein, for example, when the residual stroke number is xe2x89xa650, in the indicator device a color marking, for example, in the form of a signaling bar, becomes visible which signalizes to the respective user in a timely fashion that a new inhalator must be obtained.
The improvement of the indicating precision possible with the dosage counting device according to the invention makes it possible to reduce the overfilling of the dispensing container, performed for safety reasons, and to thus reduce the residual amount of active substance in the dispensing container.
An advantageous embodiment of the invention with respect to a particularly reliable further switching of the first counting ring is provided in that the switching finger is spaced from the rotational axis and is positioned at a slant thereto. Accordingly, it is possible in a kinematically beneficial way to bring the switching finger into engagement with control elements provided at the counting ring and to tilt the switching finger subsequently about a tilting axis which extends substantially transversely to the longitudinal direction of the switching finger. The positioning angle of the switching finger relative to a radial plane defined by the counting ring is preferably in the range of 30 to 60xc2x0. In this connection, sufficiently large transport paths of the switching fingers result in connection with favorable force ratios.
According to a preferred embodiment of the invention, the switching finger can be deflected out of an initial position into an end position which is slanted relative to the initial position, wherein an engagement portion of the switching finger is forced already in the initial position thereof in an elastically yielding fashion into an engagement position with the first counting ring. Accordingly, in a reliable way it is ensured that each individual dispensing stroke of the inhalator is counted by the dosage counting device.
An advantageous embodiment of the invention with respect to an especially beneficial conversion of the dispensing stroke of the dispensing container of the inhalator into a further switching movement required for operating the dosage counting device is provided in that an arm part is provided that is coupled with the switching finger wherein the arm part and the switching finger form an elbow joint mechanism. This ensures for still advantageous force ratios a comparatively long switching finger transport distance so that it is possible to space the numbers provided on the first counting ring so far apart from one another that only one individual number of the counting ring is visible within the window portion, respectively.
The return force required for returning the switching finger can be provided in an advantageous way by elastic deformation of the switching finger or of the actuator elements which are coupled with the switching finger. The switching finger is comprised advantageously of a plastic material, preferably a thermoplastically formable plastic material.
An advantageous embodiment of the invention with respect to a reliable actuation of the switching finger is provided in that the arm part and the switching finger are connected to one another by means of an actuation portion. The actuation portion forms in an advantageous way a contact surface facing a shoulder portion of the dispensing container of the inhalator, which contact surface, upon lowering of the dispensing container within the context of a dosage stroke, is deflected from its initial position, in particular, is moved substantially in the axial direction of the dispensing container.
The arm part and the switching finger are formed as a monolithic part according to a preferred embodiment of the invention. Advantageously, in this embodiment the actuation portion is provided in the connecting area between the arm part and the switching finger. The movability of arm part and switching finger relative to one another results substantially from the elasticity of the material in the area of the corresponding transition locations. The geometry of the transition portions is selected such that at least in the context of the determined number of dosage strokes no considerable material fatigue or cross-sectional weakness is caused in the corresponding connecting portions.
An advantageous embodiment of the invention with respect to an especially high functional reliability of the dosage counting device is provided in that at least the first counting ring, preferably also the second counting ring, and in a particularly advantageous way also the switching finger are made of POM. The remaining components of the inhalator can be made of comparatively inexpensive plastic materials, such as, for example, polystyrene or polyethylene or other, preferably thermoplastically deformable, plastic materials.
An embodiment of the invention which is especially advantageous with respect to an especially compact and functionally reliable configuration of the dosage counting device is provided in that the switching finger, the actuation portion and the arm part extend substantially arc-shaped about the rotational axis of the first counting ring. The radius of this arc corresponds advantageously substantially to half the diameter of the shoulder formed on the dispensing container. In this way, it is advantageously possible to arrange the counting ring switching device directly in the area of the dispensing valve of the inhalator. In this way, it is advantageously possible to form a housing portion provided for guiding the dispensing container of the inhalator by a separately formed tubular element which is placed onto the mouthpiece of the inhalator.
An advantageous embodiment of the invention with respect to a reliable counting of the individual dosage strokes is provided in that a reverse motion check device is provided which has a locking pawl which engages, at least upon further transport of the first counting ring by one counting step, a correspondingly formed engagement portion provided on the counting ring.
As an alternative, or also in combination with such a locking pawl, it is also possible to prevent rotation of the first counting ring counter to the counting ring switching direction by a frictional locking mechanism. The counting ring switching device; and, advantageously, also the reverse motion check device are formed according to a special aspect of the present invention such that they count each dispensing or dosage stroke.
In an advantageous way, the switching mechanism is formed such that the first counting ring is actuated and rotated farther even when a dispensing stroke has been performed only incompletely. An advantageous embodiment of the invention with respect to an especially easy-running configuration of the reverse motion check device is provided in that several locking pawls are provided which can be brought into engagement with corresponding engagement portions formed on the first counting ring, wherein the individual locking pawls are arranged in a staggered arrangements to one another such that these locking pawls are each in different engagement states.
The length of the arm part and the length of the switching fingers as well as the position of the arm part and of the switching finger are adjusted such that upon displacement of the actuating element by a predetermined travel stroke the engagement portion of the switching finger is displaced in the circumferential direction of the first counting ring by a travel distance whose length is substantially identical to the step length of a scale provided at the periphery of the first counting ring. In this way, it is possible advantageously to display the number combination required for the indication of each individual counting step in a uniquely defined way.
An advantageous embodiment of the invention with respect to an especially reliable counting and indication of the individual dosage strokes is provided in that the scale of the first counting ring has the numbers of 0, 1, 2 . . . to 9, wherein these numbers are provided with identical peripheral division on the periphery of the first counting ring. These numbers can be, for example, applied by screen printing onto the counting ring. However, according to an especially preferred embodiment of the invention, the scale is burned by means of a laser writing method directly into the plastic material of the counting ring.
Also, the scale of the second counting ring has in an advantageous manner the numbers 0, 1, 2 . . . to 9. The application of the numbering of the second counting ring can be carried out in the same way as explained above with respect to the first counting ring.
An advantageous embodiment of the invention with respect to counting a comparatively large number of strokes is provided in that the scale of the second counting ring has the numbers 0, 1, 2 . . . to 20. In this way it is advantageously possible to count with only two counting rings a total of 200 dosage strokes. In particular, in this embodiment on the first counting ring the series of numbers 0, 1, 2 . . . to 9 is arranged several times in sequence, in particular, 2 to 3 times. This shortens considerably the transport distance for further switching of the first counting ring.
The coupling device for coupling the second counting ring with the first counting ring for a step-wise rotation of the second counting ring together with the first counting ring comprises advantageously a tongue which is formed on the first counting ring and which is elastically deflectable and can be brought into direct engagement with an engagement portion of the second counting ring. This tongue is deflected according to a preferred embodiment of the invention by a contact nose that is stationarily arranged relative to the first counting ring which maintains the elastically deflectable tongue in engagement with the second counting ring across an angle interval which corresponds exactly to the step angle for further switching of the second counting ring. For realizing corresponding gear ratios, if needed, several such contact noses can be formed on a component of the inhalator which is stationarily arranged relative to the first counting ring. If needed, it is also possible to form several elastically deflectable tongue elements on the first counting ring which are designed to be brought into direct contact with the second counting ring.
An advantageous embodiment of the inhalator with respect to an especially reliable operation of this coupling device is provided in that the second counting ring comprises a bearing portion which is inserted into the first counting ring so as to be rotatable or is placed onto the first counting ring. By providing corresponding circumferential grooves and engagement portions between the two counting rings, it is possible to support the two counting rings so as to be rotatable relative to one another and to prevent an axial pulling-apart of the two counting rings. The position of the: first counting ring relative to the contact noses can be maintained in an advantageous way by a circumferential groove provided on the first counting ring.
The rotation of the second counting ring counter to the switching direction is advantageously prevented by an additional reverse motion check device.